1. Field of the Invention
The present invention relates to a mobile terminal and, more particularly, to a mobile terminal having a global positioning system receiver.
2. Description of the Related Art
In the early 1970's, global positioning system (GPS) was introduced as a military system for locating objects on the ground. GPS is today commonly used a geographic information system for aiding as the navigation device of airplanes, ships and vehicles. GPS detects a position of a person, a car or a mobile device. Personal mobile GPS receivers are utilized to explore unknown areas or detect a position of a target on earth.
GPS positional data contains an error range of approximately 50 meters for military, and 200 meters for non-military use. Differential GPS (DGPS) provides a reduced error range of 5 meter.
Referring to FIG. 1, a GPS includes twenty-four satellites and two primary satellites. The majority of the satellites are maintained at an altitude of 20200 km. Four satellites are non-uniformly disposed at an altitude of six orbital surfaces. Each of the four satellites is spaced apart at 60 degree intervals. The four satellites receive simultaneously four or more signals measuring an object's position on the ground. The more signals received by more satellites, the more accurate the measurement is of an object's position.
Referring to FIG. 2, a general folder type mobile terminal comprises a cover part 200, a body part 100 and a hinge part 300 connecting the cover part 200 and the body part 100. The cover part 200 includes a display unit 210, and a speaker and a vibrating motor inserted at an upper side of the display unit 210. The body part 100, on which a keypad is formed, includes a main printed circuit board. The display unit 210 receives power from the main printed circuit board or various signals through a flexible printed circuit board. The flexible printed circuit board provides an electronic product that is compact, light, heat resistant, flexible and chemically resistant.
Referring to FIG. 3, the conventional mobile terminal receives signals including global positioning system (GPS) and code division multiple access (CDMA) signal through a GPS/CDMA antenna unit 105. A CDMA transceiver block 120 transmits and receives the CDMA and GPS signal. A GPS receiver 130 processes a received GPS signal. A diplexer 110 selectively transmits a received signal from the antenna unit 105 to the CDMA transceiver block 120 or to the GPS receiver 130. A mobile system modem (MSM) 140 controls transmission and reception of signals form the CDMA transmitting/receiving block 120 and the GPS receiver 130.
The GPS receiver 130 and the CDMA transceiver block 120 are adjacent and share the antenna unit 105. The CDMA mobile terminal in North America supports both the CDMA transceiver block 120 and the GPS receiver 130 using one antenna unit 105. A signal distributor 10 such as a diplexer, an RF switch such as single pole double throw (SPDT) switch, or a single pole triple throw switch (SP3T) switch, or the like switches signal from the antenna unit 105 to either the CDMA transceiver block 120 or the GPS receiver 130.
When the antenna unit 105 receives the CDMA signal, the diplexer 110 transmits the signal to the CDMA transceiver block 120 using a diplexer 110. Meanwhile, when the GPS signal is received by the antenna unit 105, the received GPS signal is applied to the GPS receiver 130. The GPS receiver 130 and the CDMA transceiver block 120 being adjacent to each other and sharing the antenna unit 105 cause signal interference to occur. Mutual signal interference between the CDMA signal and the GPS signal degrades a receive performance of the GPS receiver 130. The conventional mobile terminal has high path loss because of the long distance between the antenna unit 105 and the GPS receiver 130.
Therefore, there is a need for improved system and method that overcomes the above problems and provides advantages over conventional signal receiving systems.